C++ LUTs


Alan Jones <sky...@...>
 

Hi All,

Just wanted to throw a quick thought in on C++ LUTs.

I've recently been dealing with Arri's Alexa. One of the more unusual
aspects of it's Log-C transform is that it changes based on the
camera's ASA.

I thought you might want to allow for LUTs which specify arguments,
as this would be required for Log-C, and may be needed or useful
further down the line.

Anyway - that was all :) When the API is ready I'd be happy to
supply S-Log, Log-C, sRGB, and Rec709 transforms both to and
from linear.

Cheers,

Alan.


Joseph Slomka <jsl...@...>
 

Alan,

It seems that this can be taken care of by having multiple colorspaces. For Arri log or Red log it is simple enough to treat each ISO rating as a separate colorspace. If you didn't want to work that way you can always create a dynamic colorspace object.

-Joseph


________________________________________
From: ocio...@googlegroups.com [ocio...@googlegroups.com] On Behalf Of Alan Jones [sky...@gmail.com]
Sent: Sunday, October 17, 2010 8:31 AM
To: ocio...@googlegroups.com
Subject: [ocio-dev] C++ LUTs

Hi All,

Just wanted to throw a quick thought in on C++ LUTs.

I've recently been dealing with Arri's Alexa. One of the more unusual
aspects of it's Log-C transform is that it changes based on the
camera's ASA.

I thought you might want to allow for LUTs which specify arguments,
as this would be required for Log-C, and may be needed or useful
further down the line.

Anyway - that was all :) When the API is ready I'd be happy to
supply S-Log, Log-C, sRGB, and Rec709 transforms both to and
from linear.

Cheers,

Alan.


Alan Jones <sky...@...>
 

Hi Joseph,

On Mon, Oct 18, 2010 at 12:50 PM, Joseph Slomka <jsl...@imageworks.com> wrote:
It seems that this can be taken care of by having multiple colorspaces. For Arri log or Red log  it is simple enough to treat each ISO rating as a separate colorspace. If you didn't want to work that way you can always create a dynamic colorspace object.
Yeah - I just thought it may be nice to have the capacity to provide
the argument. That way
you're not filling a list of color spaces with variations of the same
one. Makes the List a little
more comprehensible.

By dynamic colorspace you mean a plugin based one? In which case this
is what I was proposing
it for.

Cheers,

Alan.


Joseph Slomka <jsl...@...>
 

Alan,

By dynamic I mean c++ or python can create colorspace configurations dynamically. That way if you are using ARRI log C You could dynamically create or alter the colorspaces to handle the different conversions that need to be made based off the iso setting. So you can use the same base configuration and automatically change the logC to reference conversion based on the iso so all of the conversion that a related to that work as expected.

-Joseph

Joseph Slomka
Color Scientist
Sony Pictures Imageworks

-----Original Message-----
From: ocio...@googlegroups.com [mailto:ocio...@googlegroups.com] On Behalf Of Alan Jones
Sent: Monday, October 18, 2010 11:32 AM
To: ocio...@googlegroups.com
Subject: Re: [ocio-dev] C++ LUTs

Hi Joseph,

On Mon, Oct 18, 2010 at 12:50 PM, Joseph Slomka <jsl...@imageworks.com> wrote:
It seems that this can be taken care of by having multiple colorspaces. For Arri log or Red log  it is simple enough to treat each ISO rating as a separate colorspace. If you didn't want to work that way you can always create a dynamic colorspace object.
Yeah - I just thought it may be nice to have the capacity to provide the argument. That way you're not filling a list of color spaces with variations of the same one. Makes the List a little more comprehensible.

By dynamic colorspace you mean a plugin based one? In which case this is what I was proposing it for.

Cheers,

Alan.